This invention relates to an article and method for its use in bone augmentation. More particularly, it relates to an implant and a method for installing the implant, especially for rebuilding the underlying bones of the upper and lower jaw of one's mouth.
In humans, bone restoration or augmentation is often required after loss of teeth. Although a significant segment of the American population wears dentures, many of these people suffer from improper retention because of a resorption of the underlying alveolar bone. Many procedures have been proposed and applied to restore alveolar bone in order to improve denture retention and stability. (See J Oral Maxillofac Surg: 41:629-642, 729,737, 801-806, 1983; 42:89-92, 150-160, 224-230, 749-750, 1984; 43:3-7, 57-60, 277-280, 469-470, 570-573, 1985; and Oral Surg. Aug. 1985 p. 146.) For various reasons, the majority of these procedures are not totally satisfactory, and new materials and methods are constantly being developed.
Recently, a new class of hydroxylapatite has been developed which is thought to be the most biocompatable hard tissue found to date (see U.S. Pat. No. 4,097,935). Hydroxylapatite (HA) is a common mineral which is mined in large quantities as the principal source of phosphate ion for a variety of common products such as fertilizers and detergents. It is also used as a tableting and anti-caking agent, and as a calcium food supplement. As vertebrate tooth and bone mineral is derived from this chemical composition, it has long been the subject of medical investigation. HA makes up the bulk of the entire skeletal system, ranging from approximately 65% of bone to 98% of dental enamel and it would seem that HA is well tolerated when implanted into bone.
The most remarkable property of this material is its reputed ability to become directly bonded to bone by what appears to be a natural bone-cementing mechanism. In addition, HA is nonresorbable, i.e., it does not break down and assimilate into the body. Because of this attractive profile, particulate hydroxylapatite (HA) is being used to preserve alveolar bones which support the teeth, augment atrophic alveolar ridges, i.e., tooth socket bones which have shrunk due to lack of function, and to fill periodontal defects. Presently, prosthetic filling materials for bones, such as HA, are delivered into the augmentation site by injecting the loose material particles via a small bore insertion syringe. However, technical problems encountered with the current delivery system include displacement of particles into unintended locations and defects in the augmentation, with extrusion and loss of particles.
Accordingly, it is an object of the present invention to provide an article and method for improved restoration of defective living bones.
It is a more particular object of the present invention to provide such an article and method especially designed for improved preservation and augmentation of atrophic alveolar ridges.
It is also an object of the present invention to provide such an implant for restoration and augmentation of bones which is simple in design, easy and inexpensive to manufacture and use, effective, reliable and safe.